Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
2002-08-12
2003-09-23
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
Reexamination Certificate
active
06623915
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to concentrated and working strength photographic color developing compositions that have improved stability, and to methods for their use. This invention is useful in the field of photography to provide color photographic images.
BACKGROUND OF THE INVENTION
The basic processes for obtaining useful color images from exposed color photographic silver halide materials include several steps of photochemical processing such as color development, silver bleaching, silver halide fixing and water washing or dye image stabilizing using appropriate photochemical compositions.
Photographic color developing compositions are used to process color photographic materials such as color photographic films and papers to provide the desired dye images early in the photoprocessing method. Such compositions generally contain color developing agents, for example 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline, as reducing agents to react with suitable color forming couplers to form the desired dyes. U.S. Pat. No. 4,892,804 (Vincent et al.) describes conventional color developing compositions that have found considerable commercial success in the photographic industry. Other known color developing compositions are described in U.S. Pat. No. 4,876,174 (Ishikawa.et al.), U.S. Pat. No. 5,354,646 (Kobayashi et al.), and U.S. Pat. No. 5,660,974 (Marrese et al.).
It is generally known that the concentrations of various photochemicals used in a photographic color developing composition must be within certain narrow limits in order to provide optimal performance. This is particularly true of “concentrates” or single-part compositions.
There is a trend in the photographic industry to provide photoprocessing compositions (including color developing compositions) in concentrated form so that the manufacturer and user need not pay for use, transport or storage of large volumes of water, and to enable use of smaller containers. Moreover, there has been a desire in the industry to provide compositions that can be used right out of their containers without the need for mixing various components (thereby reducing mixing errors), such as in what are known as “automatic replenishing” processors.
One concentrated form known in the art is a chemical paste or slurry, as described for example in EP-A-0 204,372 (Chemco) and EP-A-0 800,111 (Fuji Photo). These formulations have still other disadvantages, namely lack of homogeneity and slow dissolution rate of solid components.
Additional small volume, ready to use color developing compositions are described in U.S. Pat. No. 5,273,865 (Loiacono et al.). These compositions are said to be free of bromides, hydroxylamines and benzyl alcohol, to include a polyol compound having 4 to 8 hydroxy groups, and to be useful for rapid access processing of photographic elements having high silver bromide emulsions only.
A very useful single-part color developing composition that is homogeneous, concentrated, and stable is described and claimed in U.S. Pat. No. 6,077,651 (Darmon et al.). Such compositions are stable from the presence of the free base form of the color developing agent and a particular amount of water-soluble organic solvent.
Stability of the color developing agents in such compositions is generally achieved using sulfite ions or any of the many conventional organic antioxidants (or preservatives) that reduce aerial oxidation rates. For example, U.S. Pat. No. 4,892,804, U.S. Pat. No. 4,876,174, U.S. Pat. No. 5,354,646, and U.S. Pat. No. 5,660,974 (all noted above) describe hundreds of possible derivatives of hydroxylamines that can be used as antioxidants in color developing compositions.
However, there is a desire in the photoprocessing industry to find additional means of stabilizing color developing compositions, especially concentrated compositions. There is also a desire to reduce the amounts of organic antioxidants including hydroxylamine derivatives for a number of reasons without losing the ability to reduce aerial oxidation.
SUMMARY OF THE INVENTION
This invention provides an aqueous photographic color developing composition having a pH of from about 7 to about 13 and comprising:
a) at least 0.0005 mol/l of a color developing agent, and
b) as a preservative for the color developing agent, from about 0.0005 to about 0.5 mol/l of a sulfur compound that is represented by one of the following Structures I, II, III, and IV:
M
1
S—R—CH(NH
2
)—COOM
2
I
M
1
S—R
1
—COOM
2
II
R
2
—S—S—R
2
III
R
3
HN—R
4
—SM
1
IV
wherein R is a divalent aliphatic linking group having at least 1 carbon atom in the chain, R
1
is phenylene or an unsubstituted-alkylene having 1 or 2 carbon atoms, R
2
is a monovalent aliphatic group having at least 2 carbon atoms and comprising a —CH(NHR
3
)—COOM
2
or —(C
1
-C
3
)alkylene-CH(NHR
3
)—COOM
2
group, R
3
is hydrogen, an alkyl group having 1 to 3 carbon atoms or phenyl, R
4
is an alkylene group, a cyclohexylene group, or a phenylene group, and M
1
and M
2
are independently hydrogen, an alkali metal or ammonium ion or methyl group.
In preferred embodiments, this invention provides a concentrated, aqueous, single-part color developing composition having a pH of from about 8 to about 12 and comprising:
a) from about 0.005 to about 1 mol/l of a color developing agent in free base form,
b) less than 0.00005 mol/l of hydroxylamine or a derivative thereof,
c) a water-miscible or water-soluble hydroxy-substituted, straight-chain organic solvent that has a molecular weight of from about 50 to about 200,
d) a buffering agent that is solvent in the organic solvent,
e) from about 0.005 to about 0.3 mol/l of a calcium ion sequestering agent, and
f) as a preservative for the color developing agent, from about 0.005 to about 5 mol/l of one or more isomers of cysteine or a hydrochloride salt thereof, homocysteine, methionine, 3-mercaptovaline, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 3-mercapto-1-benzoic acid, mercaptoacetic acid, one or more isomers of cystine or hydrochloride salts thereof, mesocystine, 3,3′-dithiobisvaline or a hydrochloride salt thereof, 2-aminoethanethiol, 2-aminoethanethiol hydrochloride, 3-aminopropanethiol hydrochloride, or any appropriate carboxylate salt thereof.
This invention also addresses the problems noted above with a two-part color developing kit comprising:
(I) a first aqueous solution having a pH of from about 9 to about 14, and
(II) a second aqueous solution having a pH of from about 3 to about 7 and comprising:
(a) at least 0.005 mol/l of a color developing agent,
(b) at least 0.001 mol/l of sulfite ions,
further comprising, in the first or second aqueous solution, from about 0.005 to about 5 mol/1 of a sulfur compound represented by one of the following Structures I, II, III, and IV:
M
1
S—R—CH(NH
2
)—COOM
2
I
M
1
S—R
1
—COOM
2
II
R
2
—S—S—R
2
III
R
3
HN—R
4
—SM
1
IV
wherein R is a divalent aliphatic linking group having at least 1 carbon atom in the chain, R
1
is phenylene or an unsubstituted alkylene having 1 or 2 carbon atoms, R
2
is a monovalent aliphatic group having at least 2 carbon atoms and comprising a —CH(NHR
3
)—COOM
2
or —(C
1
-C
3
)alkylene-CH(NHR
3
)—COOM
2
group, R
3
is hydrogen, an alkyl group having 1 to 3 carbon atoms or phenyl, R
4
is an alkylene group, a cyclohexylene group, or a phenylene group, and M
1
and M
2
are independently hydrogen, an alkali metal or ammonium ion or methyl group.
Still again, this invention also provides a method of making a working strength color developing composition from the two aqueous solutions noted above comprising:
A) combining the first and second aqueous solutions noted above in such a manner that the volume ratio of the first aqueous solution to the second aqueous solution is from about 2:1 to about 1:2 and,
B) simultaneously or subsequently, diluting the first and second aqueous solutions with water in such a manner as to dilute the first aqueous solution at
Haye Shirleyanne E.
Huston Janet M.
Le Hoa Van
Tucker J. Lanny
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